neon license plate wiring

i have a 95 cavalier and recently bought one of those neon license plate holders. i was wondering if anybody had experience wiring one of these straight into the tail lights{w/o any shorting out}. There is 2 wires from the neon and 3 or 4 wires in the tail light set up.

do you want the neon to come on just when the taillights are on, all the time, with a switch, or when you hit the brakes?